This invention relates to valves in general and, more particularly, to a diverter valve for changing a flow path of a fluid.
A diverter valve has utility in a variety of fluid handling applications. One of these applications is directing water to and from a backwash filter, such as is used in a swimming pool. In this application, the diverter valve changes the flow path of water between a filter path and a backwash path. In the filter path, water from the swimming pool passes through the filter and then flows back to the swimming pool. In the backwash path, water from the swimming pool passes through the filter in an opposite direction and then flows to a drain. When water flows through the filter path, media in the filter, such as sand, removes and retains contaminants from the water. When water flows through backwash path, the water flushes the contaminants from the media and carries the contaminants to the drain.
Diverter valves used with backwash filters typically fall into one of two categories: multiport valves and slide valves. An example of a multiport valve is shown in U.S. Pat. No. 3,712,268 to Erlich et al., the disclosure of which is incorporated herein by reference, while an example of a slide valve is shown in U.S. Pat. No. 4,714,551 to Bachhofer et al., the disclosure of which is incorporated herein by reference.
A typical multiport valve has an upper body rotatably mounted to a lower body. One or more annular sealing rings are disposed between the upper and lower bodies to prevent external and/or internal leakage. The lower body has a plurality of ports, while the upper body has a plurality of passages extending therethrough. Selective rotation of the upper body causes the passages to interconnect the ports to produce a desired flow path. Since the ports are interconnected through the upper body, water flow through the multiport valve is non-linear. As can be appreciated, non-linear flow through the multiport valve creates a sizable pressure drop.
In addition to introducing a sizable pressure drop, the typical multiport valve tends to be expensive to manufacture because of the complexity of its construction. The typical multiport valve also tends to be difficult to actuate because the entire sealing ring is in frictional engagement with either the upper or the lower body when the upper body is rotated. This large amount of frictional engagement causes the sealing ring to wear out quickly, thereby necessitating frequent replacement.
A typical slide valve for use with a reverse flush filter has a cylindrical body with five ports formed therein. First, fourth and fifth ports are disposed on one side of the body, while second and third ports are disposed on the other side of the body. When the valve is in a filter position, fluid from a swimming pool enters the first port, exits the second port, passes through the filter, enters the third port and passes back to the swimming pool through the fourth port. When the valve is moved to a backwash position, fluid from the swimming pool enters the first port, exits the third port, passes through the filter in an opposite direction, enters the second port, and then passes to a drain through the fifth port.
A control rod having a plurality of valve elements secured thereto is disposed in the body and is longitudinally slidable therein. Often, the control rod is spring-biased toward a filter position. A plurality of seat rings are radially disposed inside the body, around the control rod. The valve elements are moveable between the seat rings and sealingly engage the seat rings to direct water between the applicable ports. As a result, neither the first and second ports, nor the third and fourth ports are aligned. Thus, water flows non-linearly through the slide valve. As can be appreciated, non-linear flow through the slide valve creates a sizable pressure drop.
In addition to creating a sizable pressure drop, the typical slide valve tends to be expensive to manufacture because of the complexity of its construction. The typical slide valve also tends to be difficult to actuate because of the long travel of the control rod. This difficulty is magnified if the control rod is being moved against a spring bias. The long travel of the control rod also tends to cause the seat rings to wear out quickly, thereby necessitating frequent replacement.
Based upon the foregoing, there is a need in the art for a diverter valve that is simple to manufacture, is easy to actuate, and does not introduce a substantial pressure drop when the diverter valve is in a filter mode. The present invention is directed to such a diverter valve.